Writ jurisdiction was held maintainable in a contractual dispute...

Writ jurisdiction was held maintainable in a contractual dispute involving a State instrumentality because the challenge concerned the applicability and interpretation of a State order amending the Public Works Financial & Accounts Rules, not merely a private contract remedy. The respondent corporation, being under State control and bound by the governing rules and circulars, was subject to Clause 36E providing equitable adjustment when tax rates change during performance. Clause 45.1 could not override that later adjustment mechanism. Denial of the revised GST benefit, when extended to other State bodies, was arbitrary and discriminatory under Article 14. The rejection letter was quashed and refund of the differential GST with interest directed.